Correlations AP Psychology

Correlations  Co-relation  It describes the relationship b/w two variables.  Example #1  How is studying related to grades? # of hours a student studies for an exam scores on the exams Find: as their hours of study increased, their grades increased.

Positive correlations Indicates a direct relationship between variables. An increased in one variable is accompanied by an increase in another variable or a decrease in one variable is accompanied by a decrease in another variable.

Example #2 How is television viewing related to grades? ask an individual to calculate the average # of hours a day he or she watches. Grades could be measured by the grade point average obtained at the end of the school year. May find: amount of TV. increased, GPA decreased.

Negative Correlation Indicates an inverse relationship b/w variables; an increase in one variable is accompanied by a decrease in another variable.

Think of correlations this way correlation is a lot like a relationship between a couple: If you have a positive relationship you both are headed in the same direction. If you have a negative relationship you go your separate ways.

How are correlations measured? Correlation Coefficients. Correlations are measured with #’s ranging from to and -1.0 are Perfect Correlations 0 indicates no correlation b/w variables. As the # increases toward +1.0, the coefficient shows an increasing positive correlation. As the # moves closer to -1.0, the stronger the neg. correlation b/w variables.

Continue from previous slide Examples: +.79 and -.79 are both strong correlations -.22 is a weak correlation Remember that the (+) and (-) indicate the direction of the relationship.

Causation? CORRELATION DOES NOT IMPLY CAUSATION. Correlation research is a process that indicates the probability that when one variable exists, the other variable will also be present or affected.

Scatter Plots/Grams Can give a visual representation of correlations.

More Scatter Plots examples

Scatter plots

Scatter plot examples

Scatter plot example

What is an IV and a DV in a correlational study. Though a researcher is not directly manipulating a situation (such as in an experiment), he/she is manipulating the data (choosing what to look at). I am doing a correlational study trying to find a correlation between height and income. My IV is height (since I have chosen or grouped people by height, it is what I chose to manipulate), my DV is income. I do a correlational study looking for a relationship between grade level and test scores. My IV is grade level, my DV is test score.